Clutch release mechanism



June 22, 1937. c; s; BRAGG ET AL CLUTCH RELEASE MECHANISM Filed June 1. 1931 INVENTOR. VCALEB 5/3466 wrap LIES/PATH BY 63% ATTO NEYS.

Fla. 3

Patented June 22, 1937 UNITED 'srATEs aoacsso PATENT oFFicE oLU'rcn amass mm Caleb 8. Bragg, Palm Beach, Fla., and Victor W.

Kliesrath, Port Washington, N. Y.,' assignors to Bragg-Klimt]: Corporation, Long lslami'city,

N.'Y.,a corporation of New York v Application June 1, 1931, Serial No. 541,394

' m (Cl. lea-.01)".

with a view to reducing this eifort that the present invention is designed. n v

The principal object of the invention is to provide a means for relieving the operator of an appreciable portion of the clutch control effort,

and to this end there is suggested the employment of an engine operated servo motor, automatic in its action, the driving element of the motor being so designed and so connected to the conventional clutch pedal as to impose a clutch releasing load upon the pedal when the engine is idling.

It is a further object, however, to so design the aforementioned parts that the mechanism falls short of releasing the clutch with an idling engine motor. With such a construction the actual release of the clutch is effected in the usual fashion by the driver, a very small amount of force being necessary, however, owing to the supplemental efiect of the servo moto In the attainment of the above objects there is suggested a vacuum operated fluid motor, the casing of which is preferably pivotally secured to 5 a rigid member, such as the engine casing, the piston of the motor being secured to the clutch pedal and tending to actuate the latter at closed throttle. The motor is preferably placed in circuit with the intake manifold of the engine, the L0 latter providing a. source of power to energize the motor, which power is proportional to the degree of the throttle opening.

A further feature of our invention lies in the manner of controlling the engagement of the .5 clutch mechanism, it being, of course, desirable to relieve the operator of a part of the clutch' spring load during the clutch engagement. .This result is automatically attained as the throttle valve is opened, the degree of rarefication with- 0 in the-servo motor being. progressively decreased as the valve is opened.

In somewhat similar clutch control mechanism heretofore designed, such for example, as disclosedin Woolson Patent No. 1,635,873,, dated July 5 12, 1927, it has been suggested to employ a separate control valve for the servo motor, which valve is usually manually controlled through the, intermediary of the engine throttle control means. Such a structure, however, defeats satisfactory operation because in every instance the motor is vented to the atmosphere through the control valve before the throttle valve can be suiiiciently ,opened to effectively accelerate the engine. The

result is that the operator almost instantly has.

- the entire burden of the clutch spring thrust upon his footwhich naturally tends to force his foot rearwardly and engage the clutch. This results in stalling the motor, if ,the throttle is not sufli ciently open, or in starting the car with a jerk, if the throttle is opened more quickly. The only manner in which the operator can avoid this action is to brace himself for the expected additional load when the throttle valve is opened.

With our device, however, this undesired result is obviated due to the progressive cutting out of the servo motor, which action is a functionof the degree of throttle control and is furthermore wholly dependent on said control. Should the throttle be opened slowly there is no appreciable load transferred to the foot of the operator which would tend to engage the clutch too quickly and stall the motor.

. A further object of our invention is to provide means for supplementing the effect of the conventional clutch spring in its normal function of pressing the clutch plates together, and to this end there is suggested means such as a supercharger for progressively increasing the engine manifold pressure above atmospheric as the throttle is opened, together with a servo motor in unimpeded circuit with the manifold and connected to operate the clutch plates, the effect of. the motor being thus progressively increased in aiding the clutch engagement.

Further objects of the invention are to provide an economical type of servo mechanism from the manufacturing, installation and service standpoints, and one which will compensate for both the space limitations of the conventional throwout clutch lever as well as the physical effort limitations referred to supra.

In order that the invention in its various aspects may be readily understood and appreciated by those skilled in the art, several phases ofthe invention are set forth hereinafter by wayof description and exemplification in the accompanying drawing. It will be readily appreciated, however, that the description and drawing are illustrative only and are not to be taken in an unnecessarily limiting sense.

Figure 1, there is provided. in combination with the conventional internal combustion engine Ill with its intake manifold l2 and'the conventional manually operated clutch throw-out lever ll, 9.,

- power, mechanism cooperatingwith both clutch and engine-in a mannerto be described in detail hereinafter. v

' The power comprisea'a fluid-operated" motor it including a cylinder or casing i8 preferably, though'not necessarily. pivotally'secured at itsclosed end l9 to the engine caseor other the convenient mounting rigidly secured to the chassis. The piston 20 of the motor is provided with usual connecting. rod 22, the latter being pivotally secured at to the clutch throwout lever 14 intermediate its fulcrum or pivotal mounting 24 and foot pad 26. A conduit 28 stop light traflic control now I prolonged periods of clutch disengagement, an.

serves to connect the interior of the motor with the intake manifold between the throttle 3|! and engine cylinders. ll is provided for operation-of the throttle 3.0.

Normal operation of the clutch throw-out lever H entails considerable effort on the part of the driver, particularly inview of thegvery heavy clutchspring 32 of transmission'of the large amount of energy from the engine crank shaft to the drive shaft. The

appreciable fatigue of the driver ensuing.

The servo motor disclosed in Figurel is, however, designed to reduce this. eifort on the partof the car operator.

At closed throttle there exists a partial vacuumin the engine manifold between the throttle and the engine cylinders,

at all times in communication with this point in the manifold, is, therefore, automatically energized when and ii for any reason the throttle is closed. This energizationof the motor is, of

course, due to the pressure differentials set up between opposite sides of the piston 20, the inner side being subjected to the rareflcationof'the manifold and ,the outer side being subjected to pressure.

The piston is thus automatically subjected to a force placing the rod 22 in tension, whenever the throttle valve is closed and the engine pistons are turning over, the degree of rarefication being a function of the position of the throttle. The object of the invention, however, is to supplement the effort .necessarylo disengage the clutch without at any time automatically effecting the disengagement or, in other words, taking the control 'away from'the driver. To this end, either or boththe area of the piston 20 and/or,

the point of engagement of the rod 22 and the lever ll is/are so determined as to tend to, but

not actually, disengage the clutch at the differential of pressure existing during the idling of the engine. The idling position of the throttle, the

aos iaso to Figure 1 with the :The usual accelerator .pedalthe "clutch the large busses and trucks.

This spring is necessarily heavy in order to maintain the clutch plates engaged during the rapid in vogue also; incurs area of thepiston 20 and the servo motor mechanical advantage of the lever are all variables which may be adjusted to effect the desired condition.

The maximum v thus imposed upon the clutch release lever when the engine is operating atclosed throttle, the load load from the servo motor is being predetermined to justfall short of slipping the clutch. It is at such a time that thedrlver usually wishes to disengage the clutch in order to shift the gears, whereupon it is'merely necessary forhim to apply a comparatively slight physical effort at the pedal pad 20. The power,

. and physlcaleffort in moving the lever-are. then shift is. made the throttle concurrent. After-the is opened and ,the clutch is progressively. en-

iga'ged, the 'servo motor being automatically and progressively cut out with increasing throttle.

' This is true inasmuch as the rareflcation within the manifold and consequently the motor is degine isa minimum and vice versa, the e'ifect of" the servo motor is a minimumvwhen andif the engine torque is a maximum; this, however ls.

exactly the'conditlon desired to obviate an automatic power clutch releaseor clutch slipping action. The degree'of the power effect with the consequent timing of the driving engagement of plates'is, therefore, a function of the throttle control The clutch movement may thus he graduated to effect a smooth engagement by,-

the concurrent decreasing effect of both the power and manual 'eifort.

As a further aspect ofour invention, there may be provided means forsupplementing the clutch spring 32 inits function of keeping the plates in non-slipping engagement; To this endva supercharger (Figure 3') is provided,'which adjunct functions as.v the throttle is opened to. prog'res sively increasethe manifold pressure resulting .in ,a superatmospheric pressure. 'With the .rnechani'sm\ disclosed, the piston 20 is thus im- 1 pelled outwardly to, increase the load upon the this condition existing by virtue of the pumping olutchplates, and this load progressively increases 'in direct proportion to .the degree of .superatmospheric pressure; but this isprecisely the end desired inasmuch as maximum clutch plate load is necessary at the time of maximum engine torque to obviate a slipping clutch, and sucha'load is imposed at wide open throttle.

There is thus provided an exceedingly simple. effective and economical power or booster mechanism which functionsat .all times as aclutch spring regulator'to aid the' operator during all phases of the clutch control.

It will be understood that'while the illustrated embodiments of the invention are-described as shown, a considerable latitude is to be permitted in construction within the range of, the claims.-

We claim: a 1. An automotive vehicle comprising, in combination with a clutch including means for keeping the clutch inengagement, an angularly movable clutch pedal, an internal combustion engine,

a throttle for said engine, and manuallyoperable means foroperating, said throttle, apressure differential operated motor, the movable element of which is operatively connected with the clutch mechanism, an unimpeded fluid transmitting connection between said motor and the intake (t manifold at a point between the carburetor and the pistons of the engine, and means for creating a superatmospheric pressure in said manifold under the control of said throttle, whereby with fluctuations of the gaseous pressure within the manifold incurred by the operation of the throttle there automatically ensues corresponding fluctuations of the gaseous pressure within the clutch motor to energize said motor and supplement the aforementioned means for maintaining the clutch engaged.

2. An automotive vehicle comprising an engine, engine controlling means, a clutch, means for engaging the clutch, a pressure differential operated motor, means positively interconnecting said motor and clutch whereby the clutch may be engaged by said motor, and means interconnecting said motor and engine whereby with operation of the engine controlling means to speed up the engine the motor is energized to supplement the first mentioned clutch engaging means to maintain the clutch in engagement.

3. An automotive vehicle provided with a clutch, means for maintaining the clutch in engagement, an intake manifold, means for varying the gaseous pressure within said manifold comprising a supercharger, a pressure differential operated motoroperably connected with the clutch, means interconnecting said manifold and motor, and control means for said motor operable to energize the same whereby the motor supplements the first mentioned clutch engaging means in maintaining the clutch tightly engaged.

4. An automotive vehicle provided with an engine and a clutch, the latter having a conventional clutch spring normally operative to maintain the clutch engaged at a predetermined load, an engine operated pressure differential operated motor operably connected to the clutch to aid the clutch spring in engaging the clutch by additionally loading the clutch, and a common means for controlling the operation of said engine and motor.

5. An automotive vehicle provided with a supercharger, a clutch mechanism including means for at a predetermined load, a pressure differential operable motor operably connected with the clutch, an unimpeded fluid transmitting connection interconnecting said manifold and motor, the aforementioned mechanism being so constructed, proportioned andarranged that the motor, when energized in one manner by virtue of its connection with the manifold, functions as an underrated power means insufficient of itself to disengage the clutch and, when energized in another manner serves to aid the first-mentioned means in maintaining the clutch engaged.

'7. An automotive vehicle provided with an engine, a supercharger, a transmission and a clutch serving to interconnect the engine and transmission, said clutch including means for engaging the same, and means for engaging the clutch to supplement the aforementioned clutch engaging means comprising a pressure difierential operated means operably connected to the clutch and operable by said supercharger.

CALEB S. BRAGG. VICTOR W. KLIESRATH. 

